By Kyle Aristophere T. Atienza and John Victor D. Ordoñez, Reporters

SUNDAY’S deadly shooting in one of the Philippines’ biggest universities could signal a bigger security issue and highlights the failure of the country’s justice system, according to political analysts.

The shooting, where at least three people died, “unmasked the hidden insecurity of the middle class that was not obvious before,” said Jairus D. Espiritu, a sociologist at the University of the Philippines.

“The killing of the former mayor right at the heart of one of the most exclusive schools in the country only showed that even the middle and upper-middle class are not safe,” he said, noting that most victims in the government’s drug war were poor.

The mayor’s assistant and a university guard also got killed.

The suspect, who is a licensed doctor from a city in southern Philippines, had accused the lady mayor of being a drug lord. He was not in police custody.

Police recovered two handguns and a silencer allegedly used by the suspect, whom police said had a long history of legal disputes with the mayor.

The suspect was out on bail for a cyber-libel charge. “This looks to be a determined assassin,” police Brigadier General Remus B. Medina, director of the Quezon City Police District who described the incident as “isolated,” told reporters on Monday.

Experts said the shooting showed the country’s culture of impunity made worse by ex-President Rodrigo R. Duterte, who had justified the killings in his anti-illegal drug campaign.

“This person would not have been emboldened to do this if he did not have a massive personal grievance based on his local context or if he did not believe that he’s doing this as part of a larger political project,” said Hansley A. Juliano, a former political science professor studying at Nagoya University’s Graduate School of International Development in Japan.

The gunman would also not have traveled from Basilan province to the Philippine capital “if he was not enabled along the way,” he added. “This was a vendetta at the local level, and this is not a new thing in the political scene in southern Philippines.”

Despite relaxed gun rules, school shootings are uncommon in the Philippines. But killings of politicians are not new in the country, especially during election season.

“The local spat was given symbolic cover because clearly, the suspect is treating his perceived political opponents as members of the partisan opposition against his political idols, such as the new President and his predecessor,” Mr. Juliano said.

He added that authorities should examine how the shooter had managed to bring this vendetta in public, on the eve of Philippine President Ferdinand R. Marcos, Jr.’s first address to Congress, for which a gun ban was enforced.

“This kind of random assassinations does pop up in many authoritarian contexts,” Mr. Juliano said, noting that the incident is no different from killings in the drug war.

Joy Aceron, convenor of transparency and accountability watchdog G-Watch, said the incident should prompt the public to push for policy engagements on justice system reform, accountability and peace.

“We should have a better prospect of improving the condition of our country to the point that random killings will no longer be a threat and impunity will no longer rule,” she said.

Mr. Medina said the shooting is unlikely to inspire future incidents. “This is just an isolated case,” he told the ABS-CBN News Channel. “It should not alarm the public.”

Mr. Medina said the gunman had entered the campus through GrabTaxi.

Quirino G. Esguerra, a lawyer for the late mayor’s family, called the illegal drug allegations against her “a big lie.” She said the suspect’s medical clinic in Lamitan City, Basilan province had been shuttered for operating without a permit.